Polydimethylsiloxane molecular layering

Fig. 23. Variation of surface layer thickness with molecular weight of the stabilizing polydimethylsiloxane (PDMS) chain. Hydrodynamic thickness <5109) PMMA particles (O), PS particles ( ), micellar dispersions (A) from viscosity data x, thickness h from surface coverage data of PMMA particles assuming a prolate ellipsoid model for the...

Zeolite membranes indicate inorganic membranes with a selective/cata-lytic layer composed of a zeolite which is crystalline aluminosilicate with the feature of a high ordered porous structure with size comparable to molecular dimension. An example of the use of zeolites as a catalyst in a multi-phase membrane reactor can be found in Shukla and Kumar (2004) who have immobilized a lipase on a zeolite-clay composite membrane by using glu-taraldehyde as a bifunctional ligand in order to carry out the hydrolysis of olive oil. An application of a zeolite-based membrane in a three-phase membrane reactor has been reported by Wu et al. (1998), where TS-1 zeoUte crystallites were embedded in a polydimethylsiloxane (PDMS) membrane in order to catalyse the oxyfunctionalization of n-hexane (from a gas phase) with hydrogen peroxide (from a liquid phase). 

Two types of SiH functional polymers were used linear polymers of varying chain length that are SiH functional at one end only, the other end being trimethylsilyl, and a polymethylhydrogensiloxane/polydimethylsiloxane (PMHS/PDMS) copolymer. These materials were synthesized in-house. Table II shows the molecular weight, polydispersity, and layer thickness determined ellipsometrically of the linear monofunctional SiH polymers. The structure of the... 

Ultra-thin polymeric film is a polymer layer of the thickness in a nanometric scale deposited on a substrate (see Figure 4.2C). Such silicone films are of great interest due to their use in many areas of scientific and technical applications. Polydimethylsiloxane (PDMS) is one of the most popular silicone-based polymers used in the preparation of silicone films. This polymer has a unique molecular structure and physicochemical properties, which make it suitable for a wide range of applications such as lubricants, sealants, adhesives, eye contact lenses, and microfluidic devices [48]. 

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